You should use the latest version of Occult. As of the end of
March 2001, the latest version is version 1.4 with the March 2001
revision to the asteroid prediction files. The March 2001 upgrade
adds the ability to keep two separate sets of asteroid elements:
the Main file of asteroid elements and the User file of asteroid
elements. For the most accurate path predictions you must enter
the asteroid elements in the user file and the epoch of these
elements must be very close to the time of the occultation event.

I have installed the Goffin star catalog for Occult. The
Goffin catalog is not necessary but it will occasionally save
time. As of March 2001, the Goffin catalog distributed with
Occult includes accurate positions for the Hipparcos stars but
the Tycho data is Tycho-1 and is not as accurate as the newer
Tycho-2 catalog positions. For this reason, I always look up the
star's positional information from the Tycho-2 catalog for my
updates. The update summaries will include the star's position
for the time of the event based on either Tycho-2 or Hipparcos
catalog data.

Instructions

Enter the asteroid elements in the User file of asteroid
elements. Note: the best method is to open the User
elements dialog (from the Asteroids program main screen,
under Asteroid elements), import the asteroid's elements
from the main file, then edit the elements to change them
to the updated values. Note: You MUST use a set of
elements with an epoch within a few hours of the event
and the epoch must be TDT (Terrestrial Dynamical Time).
Unless stated otherwise, the asteroid elements
distributed with IOTA updates should be TDT based.

Enter the star position, as a one-off star, in J2000
coordinates with proper motion to the date/time of the
event. The asteroid update summary and all Occult plots
include the star's position in J2000 coordinates with
proper motion to the time of the event (based on Tycho-2
/ Hipparcos)..

Search for the occultation using the USER elements and
the ONE-OFF catalog.

Plot the occultation path from the occelmnt.* file
generated in step 3.